Fixator with outrigger

ABSTRACT

An external fixator includes a main body and an outrigger for extending over a fractured joint, such as a wrist joint. The main body can be positioned next to a right arm, or flipped over and positioned next to a left arm. The outrigger is attachable to extend either to the left or to the right of the main body, as appropriate. A distal body is removeably connectable to the distal end of the main body, and the distal body can be affixed to bone on the opposite side of the fracture to immobilize the joint where the fracture occurs. The distal body is connected to the main body with an adjustable securement section which provides six degrees of adjustment freedom. The outrigger is attached to the main body through a slide plate in a dual rail configuration which provides two dimensions of adjustment. Fragment pin supports ride in a track of the outrigger, and provide seven degrees of adjustment freedom for directed fixation of fragments at the fracture site. The major components of the fixator are molded of plastic. A surgical technique using the fixator includes immobilizing the joint for an initial healing duration and retaining fragment pins in place during a secondary healing duration.

CROSS-REFERENCE TO RELATED APPLICATION(S)

[0001] None.

BACKGROUND OF THE INVENTION

[0002] This invention relates to external bone fixators for settingfractures of the human skeleton. In particular, this invention relatesto a modular bone fixator assembly for setting fractures of the distalradius and other bones. This invention improves upon the earlierinventions described in U.S. Pat. Nos. 6,056,748 and 6,283,964, bothentitled MODULAR FIXATOR ASSEMBLY, which are incorporated herein byreference.

[0003] The prior art is replete with external bone fixator devices whichare used for setting various bone fractures. Many external bone fixatordevices employ transcutaneous pins (e.g., K-wires), stakes, screws orother types of bone fasteners, which are secured in the bone on opposingsides of the fracture. The pins are then secured to an external splintdevice. The external splint device may use various articulations toadjust its position relative to the bone fasteners. During the fixationsurgery, the bone pieces at the fracture may be realigned by thesurgeon. The various articulations in the external splint device mayassist the surgeon in realigning the bone pieces. Once the externalsplint device is secured to the bones and the bone pieces are in thedesired alignment positions, the articulations in the fixator are lockedin place to maintain the bone alignment for a healing duration.

[0004] Some of these external bone fixator devices are especiallyadapted for repairing fractures of the distal radius. This type offracture often involves a fracture site close to the distal head of theradius. Fractures of the distal head of the radius are commonly referredto as Colles' fractures. Such fractures may be reduced using bonefasteners set on the distal side of the fracture in the metacarpal boneand bone fasteners set on the proximal side of the fracture in thedistal half of the radius.

[0005] It has been recognized that it is desirable for the wrist to havea certain degree of mobility during the treatment of wrist fractures.However, prior art fixator devices which employ longitudinal tractionapplied by proximal and distal pins generally do not allow motion at thewrist without crossing the joint during the period of fractureimmobilization.

[0006] Accordingly, there is a substantial need for improved externalfixator devices. The fixator devices need to be strong, rigid anddurable, to withstand any forces or inadvertent blows to which thefracture sight is subjected. The fixator devices must be lightweight, soas to movable by the patient without extreme difficulty. The fixatordevices should be reasonable in manufacturing cost and difficulty. Thefixator devices should facilitate a wide range of surgical techniques,to permit the surgeon to best adapt to the particular fracture and toprovide the best mode of healing.

BRIEF SUMMARY OF THE INVENTION

[0007] The external fixator of the present invention includes a mainbody and an outrigger. The main body is attached to a long bone on oneside of a fracture, and holds the outrigger so the outrigger issupported over the fracture site. The outrigger is preferably attachableto extend either to the left or to the right of the main body. In oneaspect of the invention, a distal body is removeably connectable to thedistal end of the main body, and the distal body can be affixed to boneon the opposite side of the fracture to immobilize the joint where thefracture occurs. The distal body is connected to the main body with anadjustable securement section, which provides multiple degrees ofadjustment freedom. In another aspect of the invention, the outriggerincludes a track for slidably receiving fragment pin supports. Due tovarious strength and rigidity characteristics of the design, thestructure of the fixator can be formed of molded plastic. The fixatorfacilitates a surgery technique wherein the joint is immobilized for aninitial healing duration and then released for a secondary healingduration, with the fragment pins retained in place.

BRIEF DESCRIPTION OF THE DRAWINGS

[0008]FIG. 1 is a perspective view of a preferred embodiment of thepresent invention configured for fixation of the right wrist, shown forsimplicity without bone pins and without detail on the heads of the setscrews.

[0009]FIG. 2 is a perspective view showing the fixator of FIG. 1,reconfigured for fixation of the left wrist and shown attached relativeto a left wrist skeleton, and also depicted using the alternativeoutrigger of FIG. 7.

[0010]FIG. 3 is an elevational view of the fixator of FIG. 1, shown withset screws and bolts removed from their respective holes 58, 60, 86, 116and 128.

[0011]FIG. 4 is an opposite elevational view of the fixator of FIG. 1,shown with bolts removed from their respective holes 58, 116 and 128.

[0012]FIG. 5 is a bottom (from the proximal) view of the fixator of FIG.1, shown with bolts removed from their respective holes 58, 60 and witha simplified distal end 18.

[0013]FIG. 6 is an end (from the distal) view of the fixator of FIG. 1,shown without the rotatable outer clamp member of the distal body.

[0014]FIG. 7 is a perspective view showing an alternative outriggerassembly.

[0015] While the above-identified drawing figures set forth preferredembodiments, other embodiments of the present invention are alsocontemplated, some of which are noted in the discussion. In all cases,this disclosure presents the illustrated embodiments of the presentinvention by way of representation and not limitation. Numerous otherminor modifications and embodiments can be devised by those skilled inthe art which fall within the scope and spirit of the principles of thisinvention.

DETAILED DESCRIPTION

[0016] A preferred fixator assembly 10 according to the presentinvention includes, as primary components, a splint or distractor device12, and an outrigger section 14. The distractor device 12 preferablyincludes a proximal pin clamp member or main body 16 and a distal pinclamp member or distal body 18. The distal body 18 is attached to themain body 16 by a securable adjustment segment 20. The outrigger section14 includes an outrigger 22 shown holding two fragment pin supports 24.The outrigger section 14 is attached to the distractor device 12 with anoutrigger attachment 26. The fixator assembly 10 is generally used forrepairing fractures of bones, especially fractures of the distal radius28 as shown in FIG. 2.

[0017] The main body 16 is adapted to be fixed to a long bone, which forthe preferred embodiment is the distal third of the radius 28. The mainbody 16 is thus somewhat elongated to reflect the elongated extent ofthe distal third of the radius 28. The main body 16 includes structurefor securing it to proximal bone fasteners 30. In the preferredembodiment, bone fasteners 30 extend through apertures or clamp openings32 in the main body 16. The clamp openings 32 extend through the mainbody 16 transversely relative to the longitudinal axis 34 of the mainbody 16. The preferred bone fasteners 30 are 3 mm bone pins or“K-wires”, but many other types of bone fasteners (such as relativelylong, thin bone screws, etc.) could equivalently be used. The bone pins30 described throughout this application may be affixed into the bone(reamed, driven, compression or distraction, etc.) as taught in U.S.Pat. Nos. 6,056,748 and 6,283,964.

[0018] During the fixation surgery, the bone pins 30 are preferablyinserted through the clamp openings 32 and surgically staked into thedistal radius 28. The bone fasteners 30 may for instance be directedthrough the main body portion 16 prior to surgical insertion into theradius 28. Alternatively, the bone pins 30 may be staked into the distalradius 28 and the main body 16 placed over the staked bone pins 30, butthreading the bone pins 30 through the clamp openings 32 prior to/duringaffixation to the bone aids in aligning the bone pins 30 relative to theradius 28. Threading the bone pins 30 through the clamp openings 32prior to/during affixation to the bone also aids in spacing and aligningthe bone pins 30 relative to the main body 16.

[0019] Once the bone pins 30 are set in the distal radius 28 andadvanced as desired relative to the clamp openings 32 in the main body16, the bone pins 30 are secured in place relative to the main body 16.For instance, the main body 16 maybe positioned relative to the bonepins 30 and the radius 28 such that the main body 16 rests on the softtissue and skin of the forearm. Alternatively, the surgeon may positionthe main body 16 spaced a short distance from the tissue of the forearm.The preferred structure to secure the bone pins 30 relative to the mainbody 16 is with set screws 36 (shown without detail). The set screws 36are threaded into set screw holes 38 which intersect the clamp openings32. Tightening of the set screws 36 will secure the main body 16relative to the surgically staked bone pins 30.

[0020] The main body 16 can be positioned in either of at least twoorientations relative to the long bone (radius 28), and the mechanismfor securing the main body 16 to the long bone (radius 28) preferablyaccommodates such multiple orientations. For instance, the main bodyportion 16 of the preferred embodiment includes two pairs of clampopenings (32 a and 32 b, 32 c and 32 d). One pair 32 a, 32 b of theclamp openings 32 extend on one side of the longitudinal axis 34 of themain body 16 (i.e., above the longitudinal axis 34 as shown in FIG. 1),and the opposing pair 32 c, 32 d of the clamp openings 32 extend on theother side of the longitudinal axis 34 (i.e., below the longitudinalaxis 34 as shown in FIG. 1). When positioned for use on the right arm asshown in FIG. 1, the upper set 32 a, 32 b of clamp openings 32 willpreferably be used, with the lower set 32 c, 32 d of clamp openings 32left vacant. Use of the upper set 32 a, 32 b of clamp openings 32 placesthe main body 16 at an elevation relative to the radius 28 which bestpositions the main body 16 relative to intended subsequent placement ofthe distal body 18 and the outrigger 22, and also minimizes the momentsthat the weight of the fixator 10 will place on the radius 28 duringnormal use.

[0021] The lower set 32 c, 32 d of clamp openings 32 provide someflexibility should the surgeon desire to use the fixator 10 at a higherelevation relative to the radius 28. However, the primary importance ofthe lower set 32 c, 32 d of clamp openings 32 is to provide flexibilityso the main body 16 can be equivalently be used on either right or leftarms. As shown in FIG. 2, the main body 16 can be flipped for use withthe left arm at the same relative height, simply by utilizing the bonepins 30 through the second (now upper) set 32 c, 32 d of clamp openings32. The preferred embodiment thus includes four clamp openings 32 a, 32b, 32 c, 32 d, with only the upper two (which can be either setdepending upon left or right orientation) being primarily intended foruse. The clamp openings 32 a, 32 b are longitudinally spaced about 1½inches apart, about two inches from the distal end of the main body 16.This spacing is adequate to support the main body 16 on the radius 28,while not coming too close to the typical Colles' fracture site in theradial head. If desired, additional bone pin clamp openings may beplaced in the main body 16, to give the surgeon additional flexibilityin placement of the bone pins 30. Similarly, if desired the main bodymay be made longer, giving the surgeon potential attachment sites intothe middle or proximal thirds of the radius 28. In any orientation, themain body 16 is intended to be affixed such that its longitudinal axis34 extends roughly parallel to the longitudinal axis of the radius 28.

[0022] The distal pin clamp body 18 of the fixator 10 is used forattachment on the opposite side of the fracture, and serves as a jointfixation body in conjunction with the main body 16 to fix the positionof the joint. In the preferred embodiment for use with a Colles'fracture, the distal body 18 is to be secured to a metacarpal andparticularly the second metacarpal 40, thereby setting the wrist andpreventing the wrist from flexing during the healing of the Colles'fracture.

[0023] Similar to clamp openings 32 of the main body 16, the distal body18 also includes transverse clamp openings 42 for transcutaneous bonepins 30 or other bone fasteners. With the distal body 18 of thepreferred embodiment, the distal transcutaneous bone pins 30 aresurgically set into the second metacarpal 40. A preferred placementlocation positions the first metacarpal pin 30 about 5 mm distal to thesecond metacarpal joint. The distal body 18 is secured relative to thebone pins 30 with set screws 44 (shown in FIGS. 1 and 3 without detail),and thereby positioned such that its longitudinal axis 46 extendsroughly parallel to the longitudinal axis of the metacarpal 40. Aspacing between the distal clamp openings 42/distal bone pins 30 ofabout one inch is appropriate for attachment into the metacarpal 40.Because the distal body portion 18 does not support the mass and theconcomitant potential moment of the outrigger 22, a single set of clampopenings 42 are provided which intersect the longitudinal axis 46 of thedistal body 18. If desired however, additional distal clamp openings maybe provided to give the surgeon additional options in securing thedistal body 18 relative to the second bone 40.

[0024] The distal body 18 is attached to the main body 16 by thesecureable adjustment segment 20. If desired, the distal body 18 can beattached with a universal joint allowing pivotal movement of the distalbody 18 to the main body 16, similar to that taught in U.S. Pat. Nos.6,056,748 and 6,283,964. For some applications, the distal body 18 maybe attached with a simple pin-type hinge, or may even be permanentlysecured relative to the main body 16. However, the preferred secureableadjustment segment 20 includes four degrees of adjustable freedom, eachseparately securable.

[0025] As a first degree of freedom, the main body 16 defines a bore 48which extends axially therein, and an extension rod 50 is received inthe bore 48. The extension rod 50 allows the fixator 10 to be lengthenedor shortened as appropriate for the particular size of patient beingtreated. Any of several mechanisms can be used so the surgeon cancontrol the extension rod 50. In the preferred embodiment, the extensionrod 50 is externally threaded. A thumb screw 52 is attached on the mainbody 16 such that it is free to rotate. The thumb screw 52 has internalthreads which mate with the external threads of the extension rod 50,such that rotation of the thumb screw 52 advances or retracts theextension rod 50. The longitudinal position of the extension rod 50 islockable via a rod set screw 54 (shown without detail in FIG. 3).

[0026] Second and third degrees of adjustment freedom are provided by ayoke section 56, which permits angular adjustment of the distal body 18relative to the main body 16. The yoke section 56 is bolted with ahorizontal bolt 58 (shown in FIG. 1 without detail) to a distal end ofthe extension rod 50 and with a vertical bolt 60 (shown in FIG. 1without detail) to a proximal end of the distal body 18. Each end of theyoke section 56 includes a peak/valley radially-toothed profile whichmates with similarly toothed profiles on the extension rod 50 and distalbody 18. Loosening of the horizontal bolt 58 permits pivoting of theyoke section 56 about a generally horizontal axis 62 defined by thehorizontal bolt 58. Loosening of the vertical bolt 60 permits pivotingof the distal body 18 about a generally vertical axis 64 defined by thevertical bolt 60. Tightening of the horizontal bolt 58 and the verticalbolt 60 secures the distal body 18 at the desired horizontal andvertical angles relative to the longitudinal axis 34 of the main body16. The horizontal and vertical bolts 58, 60 preferably includehexagonal recesses to permit tightening and loosening with an allenwrench. Alternatively, a hexagonal head or a head for a flat or Phillipsscrewdriver, or even thumbscrews may be used.

[0027] As a fourth degree of adjustment freedom, the distal body 18 isprovided as a central rod 66 (shown in FIG. 6 and in dashed lines inFIG. 5) with a rotatable outer clamp member 68. A set screw 70 (shownwithout detail in FIG. 1) is provided in a mating threaded hole in therotatable outer clamp member 68. With the set screw 70 loosened, theouter clamp member 68 freely rotates relative to the central rod 66.With the set screw 70 tightened, the outer body 68 is secured to thecentral rod 66. Further, the set screw 70 can be fully loosened topermit the outer clamp member 68 to be readily removed from thesecureable adjustment segment 20.

[0028] If desired, additional degrees of adjustment freedom may beprovided by the securable adjustment segment 20. For instance, theextension rod 50 and/or bore 48 may be shaped and configured to permitrotation between the main body 16 and the extension rod 50. The rod setscrew 54 could then function to secure the position of the extension rod50 relative to the main body 16 both longitudinally and rotationally. Asanother example, the rotatable outer clamp member 68 may be slidable onthe central rod 66 to permit extension of the distal body 18. The setscrew 70 would then function to secure the position of the outer clampmember 68 relative to the distal body 18 both longitudinally androtationally.

[0029] One purpose of the adjustment freedom provided by the secureableadjustment segment 20 is to maximize the options available to thesurgeon with respect to placement of the bone pins 30 into the secondbone (i.e., in the preferred embodiment, into the second metacarpal 40).In particular, the fixator 10 can be secured both to the radius 28 andto the second metacarpal 40 with the secureable adjustment segment 20fully loose, allowing the surgeon ease of motion to stake the bone pins30 through the fixator 10 and into the bone. A second purpose of theadjustment freedom provided by the secureable adjustment segment 20 isto maximize the options available to the surgeon with respect to thehealing orientation of the bones at the fracture site. After the fixator10 is secured both to the radius 28 and to the second metacarpal 40, thesurgeon can then manipulate the wrist joint to the desired bone healingposition, including the appropriate reduction, distraction, palmerflexion and ulnar deviation. The surgeon can perform the desiredmanipulation of the wrist joint either by applying pressure directly onthe wrist joint itself or with the aid of the fixator 10 by properlymoving the main body 16 and distal body 18 to thereby manipulate thebones. Once the wrist joint is in the desired bone healing position, thebolts 58, 60 and the set screws 44, 54, 70 are fully tightened so thewrist position is rigidly held by the fixator 10.

[0030] While traditional fixation can be performed with the distractordevice 12, the present invention particularly contemplates use fordirect fragment fixation. Direct fragment fixation is performed with theoutrigger section 14. The outrigger 22 is preferably removably attachedto the main body 16. The outrigger 22 may be attached to the main body16 during surgery, that is, after fixation of the main body 16 to theradius 28 and the distal body 18 to the second metacarpal 40, and aftersecurement of the securable adjustment segment 20. By attaching theoutrigger 22 to the main body 16 after such fixation and securement, thesurgeon has better access to the wrist joint during the fixation andsecurement steps. Alternatively, the outrigger 22 may be attached to themain body 16 prior to surgery or prior to the fixation and adjustmentsteps. As an alternative but less flexible embodiment, the outrigger 22may be permanently secured to the main body 16.

[0031] If desired, the outrigger 22 may be attached to the main body 16by a mounting member with thumb gear as taught in U.S. Pat. Nos.6,056,748 and 6,283,964. In the preferred embodiment, however, theoutrigger section 14 is attached to the distractor device 12 with a dualsliderail configuration provided by the outrigger attachment 26. As bestshown in FIGS. 5 and 6, the outrigger attachment 26 includes a rail 72disposed on the main body 16, a rail 74 disposed on a flange 76 of theoutrigger 22, and a slide plate 78 which operates in conjunction withthe two rails 72, 74. As best shown in FIG. 6, the main body rail 72 isprovided on a side of the main body 16 toward the fracture site. Whilethe main body rail 72 could extend in any direction, the main body rail72 in the preferred embodiment extends longitudinally, parallel to thelongitudinal axis 34 of the main body 16. This orientation provides themain body rail 72 while adding the minimal amount of mass and bulk tothe main body 16. The main body rail 72 mates in sliding engagement witha first slide recess 80 provided on the slide plate 78.

[0032] On opposing sides of the main body rail 72, the slide plate 78abuts rail plate portions 82 of the main body 16 to provide for maximumvertical stability of the outrigger 22. The rail plate portions 82 couldbe co-planar or in parallel planes, but the preferred rail plateportions 82 on the main body 16 extend at angles to each other to bettermatch a generally cylindrical outer profile of the main body 16.

[0033] As best shown in FIG. 5, a second slide recess 84 is provided onthe opposite side of the slide plate 78, facing away from the main body16. The second slide recess 84 extends at an angle and preferablyperpendicular relative to the first slide recess 80. The outrigger rail74 on the flange 76 of the outrigger 22 mates in sliding engagement withthe second slide recess 84. On opposing sides of the outrigger rail 74,the slide plate 78 abuts the outrigger flange 76 to provide for maximumhorizontal stability of the outrigger 22. The abutment sides of thepreferred outrigger flange 76 are co-planar.

[0034] For both the outrigger rail 74 and the main body rail 72, thepreferred shape of the rail is a dovetail having a head and a neck whichis narrower in cross-section than the head. This shape securely limitsmovement of the sliding engagements other than in the slide direction,while still being relatively easy to mold. The preferred length of theslide rails 72, 74 is about 1½ inches, which has been found sufficientto adequately support the outrigger 22 relative to the main body 16while still permitting ½ inch or so of adjustability without significantloss of rigidity.

[0035] In the preferred outrigger attachment 26, two distinct modes ofseparability are available. The main body rail 72 is exposed at itsdistal end, and the mating recess 80 of the slide plate 78 is exposed atits proximal end. This allows removal of the slide plate 78 from themain body 16 simply by sliding the slide plate 78 fully in the distaldirection. Attachment of the slide plate 78 to the main body 16 isperformed oppositely, by properly positioning the slide plate 78relative to the main body 16 and sliding the slide plate 78 in theproximal direction.

[0036] The outrigger rail 74 is exposed at its anterior end, and themating recess 84 of the slide plate 78 is exposed at both its anteriorand its dorsal end. This allows removal of the outrigger 22 from theslide plate 78 simply by pulling upward on the outrigger 22. Because themating recess 84 of the slide plate 78 is exposed at both ends, theoutrigger 22 can be removed in the upward direction regardless of theorientation of the slide plate 78, that is, regardless of whether themain body 16 is positioned for a right arm with the outrigger 22extending to the right (FIG. 1) or flipped over and positioned for aleft arm with the outrigger 22 extending to the left (FIG. 2).Attachment of the slide plate 78 to the main body 16 is performedoppositely, by properly positioning the outrigger 22 relative to theslide plate 78 and pushing downward.

[0037] The two modes of separability give the surgeon flexibility indetermining when and how to attach the outrigger 22 to the main body 16.The slide plate 78 maybe attached to the main body 16 before or aftersecuring the main body 16 to the radius 28. Similarly, the outrigger 22may be attached to the slide plate 78 before or after other portions ofthe surgical procedure. The sliding motion also permits infinite fineposition adjustability of the outrigger 22. In particular, the outrigger22 should be placed with 1 cm of clearance over the radial articularsurface.

[0038] Releasable securements are provided for securing the rails 72, 74relative to the their respective slide recesses 80, 84. A first setscrew in set screw hole 86, best shown in FIGS. 1 and 3, is used to setthe vertical height of the outrigger 22 relative to the main body 16. Asecond set screw in mating set screw hole 88, best shown in FIGS. 1 and5, is used to fix the longitudinal extent of the main body 16 relativeto the outrigger triangle 22. Both of these set screws 86, 88 are easilyaccessible to the surgeon from the top of the fixator assembly 10. Asimilar set of set screw holes 86, 88 is positioned on the other side ofthe main body 16, for use when the outrigger 22 is attached to extend tothe left over a left arm (FIG. 2).

[0039] If desired, the outrigger can be provided as the I-shapedmetallic member shaped as taught in U.S. Pat. Nos. 6,056,748 and6,283,964. In the preferred embodiment, however, the outrigger 22 isprovided with a rigid triangular shape projecting generallyperpendicular to the outrigger flange 76, best shown in FIG. 5. Thetriangular shape is inherently very strong, particularly againstdeflection from any cantilevered bending stresses placed on theoutrigger 22. The triangular shape generally conforms to the anatomicalconfiguration of the distal radius 28. In particular, the coronalanatomy of the radius 28 proceeds from the radial styloid backward at anangle of about 102° to 110 ° (depending upon the anatomy of theparticular patient) relative to the longitudinal axis of the radius 28.The triangular shape of the outrigger 22 proceeds back from a distalcomer 90 at an angle 92 which should be between about 95° and 118 °relative to the longitudinal axis 34 of the main body 16. The angle 92of the outrigger 22 preferably proceeds at 98° to 115° relative to thelongitudinal axis 34 of the main body 16, more preferably at 102° to110° (i.e., coinciding with the 12-20° angle of the distal head of theradius 28), with a most preferred value being 110°. This angle 92 notonly conforms to the anatomical configuration of the distal radius 28,but also provides an outrigger shape which is inherently strong and wellsupports the cantilevered stresses placed on it by the fragment fixationpin supports 24. That is, a proximal leg 94 cooperates with a distal leg96 to stabilize and strengthen the outrigger 22. Rigidity is enhancedbecause the proximal leg 94 and the distal leg 96 are well separated attheir attachment to the outrigger flange 76. The preferred outriggertriangle 22 extends from the flange 76 for nearly three inches, but isstill sufficiently long because the triangle 22 is over two inches wideincluding a nearly one inch attachment to the flange 76.

[0040] The preferred triangular shape only has the distal leg 96 whichextends backward at an angle of 110°, with the proximal leg 94 extendingforward at an angle of 70°. Only the distal leg 96 is expected to beused for any particular fixation. Of course, when the fixator 10 is usedon the opposite arm (from right to left), the direction in which theoutrigger 22 faces is reversed (from right to left), and the oppositeleg 94 of the triangular shape becomes the more distal of the two legs94, 96.

[0041] The dual slide rail configuration gives two degrees of freedom inplacing the outrigger 22 with respect to the main body 16. If desired,an additional degree of freedom may be provided as depicted in thealternative outrigger 150 of FIG. 7. A securable hinge 152 including atightening bolt 154 is provided between the base of the triangle 22 andthe flange 76. This securable hinge 152 allows pivoting of the triangle22 relative to the main body 16, about a horizontal axis 156 parallel tothe longitudinal axis 34 of the main body 16. The tightening bolt 154has a head with a slot 158 for a flat head screwdriver. By tightening ofthe tightening bolt 154, the rigid securability of the outriggertriangle 22 relative to the main body 16 can be maintained at theposition ultimately selected by the surgeon.

[0042] The legs 94, 96 of the outrigger 22 define tracks having asliding recess 98. As best shown in FIGS. 1 and 4, the sliding recess 98includes opposing lip sections 100, which assist in supporting andholding the fragment pin supports 24. The track configuration of theoutrigger 22 is inherently strong and rigid while still being relativelylightweight.

[0043] The preferred sliding recess 98 has an open end 102. This openend 102 permits removal of the fragment pin supports 24 from the track98. Thus, the surgeon can determine how many fragment pin supports 24should be lined up in the track 98 for any particular surgery. Ifdesired, the first fragment pin support 24 can be secured in placebefore the second (or third, etc.) fragment pin support 24 is placedinto the track 98.

[0044] The outrigger 22 securely and adjustably locates the fragment pinsupports 24. If desired, the fragment pin supports maybe similar tothose described in U.S. Pat. Nos. 6,056,748 and 6,283,964. However, thepreferred fragment pin supports 24 shown herein are molded plasticstructures. The preferred fragment pin supports 24 provide seven degreesof adjustment freedom in locating the fragment pins 130 into the distalradius 28.

[0045] As a first degree of adjustment freedom and best shown in FIGS. 1and 4, each fragment pin support 24 includes a knob bolt 104 which rideswithin the track 98. The surgeon can select the desired location of eachknob bolt 104 in the track 98. The knob bolt 104 has a head 106 on athreaded shaft section 108. The head 106 mates with the track 98including the opposing lip sections 100, to hold the shaft section 108rigidly upright with respect to the outrigger 22. A tightening nut 110is used on the shaft 108 to releaseably secure the knob bolt 104 at theselected location in the track 98.

[0046] If desired, the head 106 of the knob bolt 104 can be elongated orotherwise have flats which mate with the walls of the track 98, to moresecurely hold the knob bolt 104 relative to the outrigger 22. However,as a second degree of adjustment freedom, the head 106 of the knob bolt104 is cylindrical without any flats. This allows the surgeon, while thetightening nut is loose, to rotate the knob bolt 104 about the generallyvertical axis defined by shaft 108 of the knob bolt 104, changing thedirection in which the fragment pin support 24 extends from the track98.

[0047] A third degree of adjustment freedom is provided by a pivot arm112. The pivot arm 112 includes a fork 114 which mates over theextending end of the knob bolt 104. The tines of the fork 114 receive apivot arm bolt 116, with one of the tines threadingly engaging threadsof the pivot arm bolt 116. Similar to the yoke section 56, the tines ofthe fork 114 may have a peak/valley radially-toothed profile which mateswith similarly toothed profiles on the projecting end of the knob bolt104. Alternatively, the frictional engagement between flat surfaces ofthe pivot rod fork 114 and the knob bolt 104 may be sufficient to securethe angular position of the knob bolt 104. Loosening of the pivot armbolt 116 permits pivoting of the pivot arm 112 about a generallyhorizontal axis defined by the pivot arm bolt 116. Tightening of thepivot arm bolt 116 secures the pivot arm 112 to the knob bolt 104 at adesired angle. The preferred pivot arm 112 has a length of less than aninch, just enough to substantially avoid interference between thefragment pin support 24 and the outrigger triangle 22.

[0048] Fourth and fifth degrees of adjustment freedom are provided by aconnecting rod 118. The preferred connecting rod 118 has a cylindricalshaft 120 which slides in a cylindrical hole in the extended end of thepivot arm 112. The cylindrical shaft 120 allows the connecting rod 118to be slid upwards and downwards relative to the pivot arm 112, and alsoallows the connecting rod 118 to be pivoted about the axis defined bythe connecting rod shaft 120. A set screw 122 (shown without detail inFIG. 6) is threaded into a threaded set screw hole in the exposed endface of the pivot arm 112. The set screw 122 can be tightened to securethe connecting rod 118 in its desired amount of extension and a desiredrotational position relative to the pivot arm 112. In the preferredembodiment with two fragment pin supports 24, one of the connecting rods118 may be longer than the other, such as having lengths of about 1½inches and 2 inches. The shaft 120 of the connecting rod 118 (which inthe preferred embodiment form the thinnest link of the fixator 10) mustbe sufficiently thick to rigidly support the pin holder 124, such as adiameter of the connecting rod shaft 120 of about ⅕ inch.

[0049] A sixth degree of adjustment freedom in the fragment pin support24 is provided by the pin holder 124. The pin holder 124 is receivedbetween the tines of a fork 126 on the end of the connecting rod 118.The tines of the connecting rod fork 126 receive a connecting rod bolt128, with one of the tines threadingly engaging the connecting rod bolt128. Similar to the yoke section 56 and the pivot arm fork 114, thetines of the connecting rod fork 126 may be flat or may have apeak/valley radially-toothed profile which mates with a similarlytoothed profile on the pin holder 124. Loosening of the connecting rodbolt 128 permits pivoting of the pin holder 124 about a generallyhorizontal axis defined by the connecting rod bolt 128. Tightening ofthe connecting rod bolt 128 secures the pin holder 124 at the desiredangular position.

[0050] The seventh degree of adjustment freedom is provided by theconnection between the fragment pins 130 and the pin holder 124. The pinholder 124 includes at least one through hole 132 for receiving thefragment pin 130. A threaded set screw hole intersects the fragment pinthrough hole 132, and a threaded set screw 134 (shown in FIG. 1 withoutdetail) is tightenable to secure the fragment pin 130 relative to thepin holder 124.

[0051] Each of the set screws 36, 44, 54, 70, 86, 88, 122, 134, thepivot arm bolt 116 and the connecting rod bolt 128, all shown in thedrawings without detail, preferably include hexagonal recesses to permittightening and loosening with an alien wrench. Alternatively, ahexagonal head or a head for a flat or Phillips screwdriver, or eventhumbscrews may be used.

[0052] The fragment pin holders 124 should have sufficient length toadequately support the fragment pins 130. In the preferred embodiment,the length of the pin holder 124 (and the length of the fragment pinthrough hole 132) is over ½ inch. The preferred surgical techniqueincludes setting the fragment pins 130 through the fragment with the tipof the fragment pin 130 extending into the healthy, intact radius 28.For the example depicted in FIG. 2, two pins 130 are set beginning inthe radial styloid and exiting on the opposite intact radial cortex, anda third pin 130 secures the dorsal fragment from dorsal and distal tovolar and proximal, again exiting in the intact portion of the bone 28.Such pin placement allows the volar tilt of the wrist to be maintained.If necessary because of the condition of the radius 28, the pin holder124 sufficiently supports the fragment pin 130 such that the tip of thefragment pin 130 may be driven merely into the fragment, with supportsufficient to reduce the fragment being provided by the fragment pinholder 124 without cross-fracture attachment into the radius 28. Thepreferred fragment pins 130 are 0.062 inch diameter wires. The wires canbe drilled free hand or using the pin holders 124 as templates.

[0053] In the preferred embodiment, one of the pin holders 124 includestwo fragment pin through holes 132. The two holes 132 are separated byroughly ½ inch and extend parallel to each other, to support twofragment pins 130 in a generally parallel spaced relationship. Thesecond pin holder 124 includes a single fragment pin through hole 132.

[0054] One of the important advantages of the preferred embodiment isthe flexibility it provides the surgeon in the surgical technique used.After the wrist is immobilized with the distractor device 12, thesurgeon may determine where to place fragment pins 130 and how manyfragment pins 130 should be used. Wire placement can be varied dependingon fracture configuration and/or surgeon's preference. The fragment pins130 may be driven into the bone fragments either threaded through thepin holder 124 or even before the fragment pin supports 24 are placedinto the outrigger track 98. After the fragment pins 130 are positionedby the surgeon, the various degrees of adjustment freedom can each betightened to secure the position of the fragments relative to theoutrigger 22, and via the main body 16 relative to the radius 28.

[0055] Further, movement of the wrist joint during healing is animportant part of the healing process. The present inventioncontemplates fixation of the fragment pins 130 even after the distalbody 18 is removed from the second metacarpal 40. That is, one preferredsurgical technique for the present invention involves two separatehealing durations. In the first healing duration, the fixator 10 issecured to the distal radius 28, to the second metacarpal 40, and to thebone fragments. Once the bone fragments begin to heal, some stress onthe joint is beneficial to promote additional healing and faster bonegrowth. After an initial healing duration when the surgeon is confidentthat fracture stability exists, a wrist-release surgery is performed, inwhich the metacarpal pins 30 are removed from the metacarpal 40 and thedistal body 18 is removed from the main body 16. After the wrist releasesurgery, the patient can attain at least a limited degree of wristflexation, which improves the secondary healing. The fragment pins 130still hold the fragments in place to ensure that the wrist is notrefractured during this secondary healing. After a secondary healingduration, a third surgery is performed to fully remove the externalfixator 10.

[0056] Another important advantage of the preferred embodiment is therange of materials which can be used. The preferred embodiment isdesigned to handle stresses of the Colles' fracture fixation by using aplastic material. The plastic material used is significantly lighterthan metals traditionally used for fixators. The plastic material used,together with the sizes and shapes discussed herein, allows the fixator10 to be sufficiently rigid without permitting the degree of bendingwhich is inherently possible in most metal fixation structures. Thepreferred material for the preferred embodiment is a high densityplastic, partially glass filled. Because this plastic material is notsufficiently strong to penetrate bone (and for FDA approval reasons),traditional metal bone pins 30 are used, but the remaining parts can allbe molded of plastic. In particular, the main body 16, the distal body18, the secureable adjustment segment 20, the slide plate 78, theoutrigger 22 and the fragment pin supports 24 are all formed of plastic.As a moldable material, manufacture of the fixator 10 can be made lessexpensive. If desired for cost or thread strength reasons, the setscrews 36, 44, 54, 70, 86, 88, 122, 134 and bolts 58, 60, 104, 116, 128described herein may be formed as traditional metal structures as well.The preferred material is an ULTEM 1000, 20% glass bead filled plastic,which is an engineered high density poly-ether-imide (PEI) plasticsuitable for orthopaedic devices and available from GE Plastics. Othersuitable plastic materials might include poly-phenyl-sul-fone (PPSU)(e.g. Amoco Radel R), polysulfone (PSU) (e.g. Amoco Udel P),polyaryletherketone (PAEK) (e.g. BASF Ultrapek), liquid crystal polymer(LCP) (e.g. Vectra); and polyketone (e.g. Amoco Kadel E).

[0057] Although the present invention has been described with referenceto preferred embodiments, workers skilled in the art will recognize thatchanges may be made in form and detail without departing from the spiritand scope of the invention. As one example, while the preferredembodiment has been described as having a “main” body and a “distal”body, for certain applications it maybe desired to heal the joint byhaving the outrigger 22 supported by the bones distal of the fracture.In the case of a Colles' fracture, this would include attaching the mainbody 16 to the second metacarpal 40 and attaching the “distal” body tothe radius 28. The relative dimension and sizes of the “main” body andthe “distal” body would be adjusted accordingly. Thus a worker skilledin the art will appreciate that the term “distal” is used as a matter ofconvenience and does not necessarily indicate the orientation of thefixator 10 with respect to the fracture. As another example, while thepreferred embodiment is intended for Colles' fractures, the inventioncould be in many respects equivalently applied to fractures of otherlong bones, such as the proximal radius, and either proximal or distalends of the ulna, tibia, fibula, humerus, or femur.

1. An external fixator for a bone fracture immediately adjacent a jointbetween a long bone and a second bone, the external fixator comprising:a main body adapted for external fixation to the long bone, the mainbody extending along a longitudinal axis generally parallel to alongitudinal axis of the long bone; an outrigger connected to the mainbody for extending over the joint and generally perpendicular to thelongitudinal axis of the main body, the outrigger defining a trackhaving a sliding recess; at least one bone fastener support riding inthe sliding recess of the track.
 2. The external fixator of claim 1,wherein the outrigger is connected to the main body by a rail structure,the rail structure comprising: a first rail extending in a firstdimension and slidably received in a mating first recess; and a firstsecurement for securing the first rail relative to the first recess. 3.The external fixator of claim 2, wherein the rail structure is a dualrail structure, the dual rail structure further comprising: a secondrail extending in a second dimension at an angle to the first dimension,the second rail being slidably received in a mating second recess; and asecond securement for securing the second rail relative to the secondrecess.
 4. The external fixator of claim 3, wherein the first and secondrails are dovetail rails having a head and a neck which is narrower incross-section than the head.
 5. The external fixator of claim 2, whereinthe first rail extends from a rail support plate, and wherein the firstrecess is defined in a recess plate, wherein the rail support plateabuts the recess plate on both opposing sides of the first rail suchthat the abutting rail support plate and recess plate stabilizes theoutrigger relative to the main body.
 6. The external fixator of claim 1,wherein the main body and the outrigger are formed of plastic.
 7. Theexternal fixator of claim 1, further comprising: a joint fixation bodyadapted for fixation to the second bone; and a securable adjustmentsegment connecting the main body to the joint fixation body, thesecurable adjustment segment having an unsecured state allowing movementof the main body relative to the joint fixation body and a secured statepreventing movement of the main body relative to the joint fixation bodysuch that the external fixator secures the joint in a fixed position,the securable adjustment segment being further adapted for removal ofthe joint fixation body from the external fixator.
 8. The externalfixator of claim 7, wherein the securable adjustment segment allowslongitudinal adjustment of the joint fixation body relative to the mainbody.
 9. The external fixator of claim 7, wherein the securableadjustment segment allows angular pivoting adjustment of the jointfixation body relative to the main body.
 10. The external fixator ofclaim 1, wherein the main body adapted for external fixation to aradius, with the outrigger connected to the main body for extending overthe wrist joint between the radius and a metacarpal for treatment of aColles' fracture.
 11. The external fixator of claim 1, wherein theoutrigger is secureable to the main body at a first position wherein theoutrigger extends over the long bone to the right of the main body and asecond position wherein the outrigger extends over the long bone to theleft of the main body.
 12. The external fixator of claim 1, wherein thesliding recess has an open end permitting removal of the bone fastenersupport from the track.
 13. The external fixator of claim 1, wherein thetrack extends generally linearly at an angle of from 98 ° to 115°relative to the longitudinal axis of the main body.
 14. An externalfixator for a bone fracture immediately adjacent a joint between a longbone and a second bone, the external fixator comprising: a main bodyadapted for external fixation to the long bone, the main body defining alongitudinal axis generally parallel to a longitudinal axis of the longbone; an outrigger connected to the main body for extending over thejoint between the long bone and the second bone and generallyperpendicular to the longitudinal axis of the main body, the outriggerbeing secureable to the main body at various positions relative to themain body; and a joint fixation body adapted for external fixation tothe second bone; a secureable joint connecting the main body to thejoint fixation body, the secureable joint having an unsecured stateallowing movement of the main body relative to the joint fixation bodyand a secured state preventing movement of the main body relative to thejoint fixation body, the secureable joint being further adapted forremoval of the joint fixation body from the external fixator.
 15. Theexternal fixator of claim 14, wherein the main body comprises aplurality of clamp openings securable to bone fasteners fastened intothe long bone, and wherein the joint fixation body comprises a pluralityof clamp openings securable to bone fasteners fastened into the secondbone.
 16. An external fixator for a bone fracture immediately adjacent ajoint between a long bone and a second bone, the external fixatorcomprising: a main body adapted for external fixation to the long bone,the main body defining a longitudinal axis generally parallel to alongitudinal axis of the long bone, the main body having a proximalsection adapted for fixation to the long bone and a distal section; anoutrigger connectable to the distal section of the main body, theoutrigger extending generally over the joint between the long bone andthe second bone in a plane which also extends over the longitudinal axisof the main body, the outrigger being secureable to the main body atvarious positions relative to the main body including a first positionwherein the outrigger extends to the right of the main body and a secondposition wherein the outrigger extends to the left of the main body. 17.The external fixator of claim 16, wherein the main body has an innerside for positioning toward the long bone and an outer side forpositioning away from the fractured bone, with the outrigger beingsolely connectable to inner side of the main body in either of twoopposing orientations which define the first position and the secondposition, with the main body being rotatable 180° about its longitudinalaxis to change between the first position and orientation wherein theoutrigger extends to the right of the main body and the second positionand orientation wherein the outrigger extends to the left of the mainbody.
 18. The external fixator of claim 16, further comprising: a bonefastener support attachable to the outrigger; and wherein the outriggercomprises a first section for use in holding the bone fastener supportsuch that the bone fastener support extends distally when the outriggerextends to the right of the main body and a second section for use inholding the bone fastener support such that the bone fastener supportextends distally when the outrigger extends to the left of the mainbody.
 19. The external fixator of claim 18, wherein the first sectionand the second section each comprise a track, the tracks joining at acommon end point extended away from the main body.
 20. An externalfixator for a bone fracture immediately adjacent a joint between a longbone and a second bone, the external fixator comprising: a main bodyadapted for external fixation to the long bone, the main body extendingalong a longitudinal axis generally parallel to a longitudinal axis ofthe long bone; an outrigger connected to the main body for extendingover the joint between the long bone and the second bone and generallyperpendicular to the longitudinal axis of the main body, the outriggerbeing adjustable in at least two dimensions relative to the main body,the outrigger being secureable to the main body in a selected position.21. An external fixator for a bone fracture immediately adjacent a jointbetween a first long bone having a first long bone longitudinal axis anda second long bone having a second long bone longitudinal axis, theexternal fixator comprising: a first rigid body defining a longitudinalaxis, the first rigid body adapted for external fixation to the firstlong bone such that the longitudinal axis of the first rigid bodyextends generally parallel to the first long bone longitudinal axis; asecond rigid body defining a longitudinal axis, the second rigid bodyadapted for external fixation to the second long bone such that thelongitudinal axis of the second rigid body extends generally parallel tothe second long bone longitudinal axis; a secureable joint connectingthe first rigid body to the second rigid body, the secureable jointhaving an unsecured state allowing pivoting movement of the first rigidbody relative to the second rigid body and a secured state preventingmovement of the first rigid body relative to the second rigid body; anoutrigger connected to the first rigid body for extending over the jointbetween the first long bone and the second bone and generallyperpendicular to the longitudinal axis of the first rigid body, theoutrigger being secureable to the first rigid body at various positionsrelative to the first rigid body; and at least one stake supportextending from the outrigger, the stake support being adjustable betweenvarious positions relative to the outrigger to hold a stake into thejoint at an incline relative to the first long bone longitudinal axis;wherein the first rigid body, the second rigid body, the secureablejoint, the outrigger and the stake support are formed of plastic.
 22. Anexternal fixator for a bone fracture immediately adjacent a jointbetween a long bone and a second bone, the external fixator comprising:a main body adapted for external fixation to the long bone, the mainbody extending along a longitudinal axis generally parallel to alongitudinal axis of the long bone; an outrigger connected to the mainbody for extending over the joint and generally perpendicular to thelongitudinal axis of the main body; at least one bone fastener supportattached to the outrigger for supporting a bone fastener relative to theoutrigger and into the joint, the bone fastener support providing atleast three degrees of securable adjustment freedom for the bonefastener with respect to the outrigger.
 23. The external fixator ofclaim 22, wherein the bone fastener support provides seven degrees ofsecurable adjustment freedom for the bone fastener with respect to theoutrigger.
 24. An external fixator for a bone fracture immediatelyadjacent a joint between a long bone and a second bone, the externalfixator comprising: a main body adapted for external fixation to thelong bone, the main body extending along a longitudinal axis generallyparallel to a longitudinal axis of the long bone; a distal body adaptedfor external fixation to the second bone; and a securable adjustmentsegment attaching the distal body to the main body, the securableadjustment segment providing at least two degrees of securableadjustment freedom for the distal body with respect to the main body.25. The external fixator of claim 24, where in the bone fastener supportprovides four degrees of securable adjustment freedom for the distalbody with respect to the main body.
 26. A method of repairing afractured wrist, comprising: performing a fixation surgery comprising:placing a plurality of radius pins of an external fixator assemblytransversely into a radius proximally of the fracture, the externalfixator assembly comprising: a support structure extending generallyparallel to the radius and perpendicular to the radius pins, the supportstructure having a proximal section which releasably holds the pluralityof radius pins, the support structure having a mid-section and a distalsection; an outrigger extending generally transversely from themid-section of the support structure, the outrigger having at least onefragment pin releasably attachable thereto; and a plurality ofmetacarpal pins releasably held by the distal section of the supportstructure; securing the radius pins relative to the support structure,thereby fixing the support structure relative to the radius; placing theplurality of metacarpal pins transversely into a metacarpal; securingthe metacarpal pins relative to the support structure, such that theexternal fixator assembly fixes the metacarpal relative to the radius;placing the fragment pin into a radial bone fragment; and securing thefragment pin relative to the outrigger; after an initial healingduration, performing a wrist-release surgery, comprising: removing themetacarpal pins from the metacarpal, thereby permitting at least alimited degree of wrist flexation; and after a secondary healingduration, performing an external fixator removal surgery, comprising:removing the radius pins from the radius; and removing thecross-fracture pin from the radius.